Efficiency of reverse osmosis desalination

The exploding need for fresh water can only be satisfied by seawater desalination. So thanks to John Morgan for this Arts Technica piece based on a new Science paper The Future of Seawater Desalination: Energy, Technology, and the Environment. John reminds us how inefficient flash distillation is:

Any desalination process that avoids the phase change will be more efficient than distillation. It takes 5.4 times as much energy to turn water at 100 C into steam at 100 C as it does to heat the water from 0 C to 100 C. Even under low pressure, vaporization takes a lot of energy.

The bottom line is that state of the art reverse osmosis plants are within 25% of the realistic minimum energy for the pumping to maintain the membrane pressure:

The authors of the perspective point out that, because osmosis is a simple matter of thermodynamics, it’s possible to calculate exactly how efficient we can make the process. And, as it turns out, we’re really quite close as these things go. A state-of-the-art facility is now within a factor of two of the theoretical energy minimum, and only 25 percent higher than the realistic minimum for the current reverse osmosis process. In short, it’s going to be tough to squeeze too much more energy out of reverse osmosis, and we’re unlikely to find an alternative method of desalination that will provide a significant boost over that.

It should be obvious that nuclear is the preferred technology for generating the reliable zero-carbon electricity required. A useful reference is the ASIRC report for Victoria Overview of Treatment Processes for the Production of Fit for Purpose Water: Desalination and Membrane Technologies [PDF]. The report estimates energy requirements for seawater desalination at about 4KWh per cubic meter of product water. Excerpts:

(…) The projected annual shortfall in Melbourne’s water supply in the future is about 93 million m3. A plant producing this amount of desalinated seawater by reverse osmosis would require around 390 GWh or about a 1% increase in Victoria’s energy requirements. Greenhouse gas emissions are related to the amount of energy produced and the energy consumption for a plant requiring 390 GWh per year would therefore release approximately 540,000 tonnes of carbon dioxide per year if coal-fired power generation was utilised. Brackish water RO desalination has a lower energy use of 1.0-2.5 kWh/m3 compared to seawater RO desalination of 4.5-8.5 kWh/m3. These energy uses and associated greenhouse gas emissions are much lower than for other technologies such as multi-stage flash distillation where the total energy consumption is between 10.5-13 kWh/m3.

(…) Interest in using nuclear energy for producing potable water has been growing worldwide in the past decade. This has been motivated by a wide variety of reasons, inter alia, from economic competitiveness of nuclear energy to energy supply diversification, conservation of limited fossil fuel resources to environmental protection, and by nuclear technology in industrial development [IAEA, 2000].

Integrated nuclear desalination plants have been operating in Japan and Kazakhstan for many years. At Aktau in Kazakhstan, the liquid metal cooled fast reactor BN-350 has been operating as an energy source for a multipurpose energy complex since 1973, supplying electricity, potable water and heat to the local population and industries. The complex consists of a nuclear reactor, a gas and/or oil fired thermal power station and MED and MSF desalination units. The sea water is taken from the Caspian Sea. The nuclear desalination capacity was about 80,000 m3/d, however part of this capacity has now been decommissioned. In Japan, several nuclear power plants have seawater desalination systems using heat and/or electricity from the nuclear plant to produce feed water make- up for the steam generators and for on-site supply of potable water. MSF was initially employed, but MED and RO have been found to be more efficient. The individual desalination capacities range from about 1000 to 3000 m3/d [UIC, 2004].

An American Wivenhoe

This is very interesting analysis from Roger Pielke Jr. explaining clearly the dam managers decision challenges:

Long-time readers may remember discussions here earlier this year about the management of the Wivenhoe Dam near Brisbane, Australia and the role of such management in the flooding of Brisbane. One of the issues in that flooding was the role of reservoir management in the magnitude of the flood, which I described as follows:

Wivenhoe Dam near Brisbane, Australia is at the center of controversy in its role in the recent flood. The dam, as is commonly the case, is expected to serve two seemingly contradictory functions. On the one hand it is a buffer against drought, meaning that it is desirable to keep it more full in the eventuality of low precipitation. On the other hand, the dam is a buffer against floods, meaning that it is desirable to keep it more empty in the eventuality of heavy precipitation. Since keeping the reservoir full and empty are not simultaneously possible, it then is necessary to balance these objectives. Since future precipitation is uncertain, the dam’s management is thus a matter of decision making under uncertainty (where risks are known) and ignorance (where they are not).

A reader (thanks DB!) passes on a lengthy article from the Great Plains Examiner out of Bismark-Mandan, North Dakota on the management of upper basin reservoirs on the Missouri River. The article describes a decision context and outcome remarkably similar to what we saw in Australia earlier this year.


Read the whole thing »

Why big dams and big ag are good for the poor

(…) The United States, Western Europe, Japan, all countries in developed parts of the world that have significant hydro potential, have used more than 80 percent of that potential. In Africa, they’ve used 3 percent.

So you have countries like Norway and Switzerland and others that have developed 90 percent of their hydro potential, then sitting on the boards of their aid agencies and the World Bank and they say to Ethiopia, “We don’t like dams. We don’t like hydropower. You can’t have it. We won’t support it.” This is done in the name of environmental concern and it’s deeply, deeply resented by these countries.

(…) In my view, there’s a deep problem with the aid business. You read the UN Millenium Development Goals and in my view they put the social cart before the economic horse. They are all about social outcomes, but nothing on the economy that’s produced those outcomes, so infrastructure doesn’t figure, agriculture doesn’t figure. These global solutions are driven by rich countries and rock stars and just sort of run from fashion to fashion.

Marc Gunther interviews Harvard development expert John Briscoe.

(…) John, who was trained as a civil and environmental engineer, has worked as an engineer in the water agencies of South Africa and Mozambique; as an epidemiologist at the Cholera Research Laboratory in Bangladesh; as a professor of water resources at the University of North Carolina; and, for the past 20 years in a variety of policy and operational positions in the World Bank. Most recently he has served as the Bank’s Senior Water Advisor and the Country Director for Brazil. John is now a professor of environmental engineering at Harvard.

This is a terrific interview — I learned several things about water resources. Unfortunately, the rich country “environmentalists” don’t like dams, or GMO. Here’s an excerpt on Brazil and the 2008 food crisis:


JB: Yes. I think the energy, water, and food—this is a bad metaphor–but they are three sides of the same coin. You can hardly deal with one without the others. They all are interrelated.

Here there’s an extremely worrying situation. Look back to the 1960s and the success of the Green Revolution. People were saying that poor countries like Bangladesh could never feed their people. We now have India, Bangladesh, all these places, essentially, self sufficient in food production. We had in the 1960s and 1970s a yield growth of 3 to 4 percent a year. This was just incredible and had huge positive impacts. Even today, food prices are less than half than what they were in 1960 in real terms. So, this has been, in my view, one of the greatest achievements of science, contributing to the well-being of billions of people.

MG: But those gains are petering out, correct?

JB: Essentially, yes. Because the scientific ingredients of the Green Revolution have largely run their course, we now have yield improvements of half a percent and one percent, with large growing populations. and markets are becoming very, very thin. When there is some disturbance, the market tips and we food crises as in 2008.

Let me give an example: I lived in Brazil for the last three years. Brazil has had an amazingly positive experience. The value of agricultural output in Brazil today is three times what is was 35 years ago and Brazil is an agricultural superpower, one of the biggest producers of bio-fuels, of soy beans, meat, fruits, etc.

It turns out that of that 300 percent increase in production, 90 percent is attributable to productivity increases. Only 10 percent of that increase is accounted for by increases in input of land, labor, and capital. Most it comes from being much smarter. This is because Brazil over this period – even through hyper-inflation, through economic crises — never stopped investing massively in agricultural research. So they have today, without anybody being a close second, a research establishment on tropical agriculture that is by far the best in the world. They’ve seen enormous returns on investment in agricultural research.

Strikingly, look at that same period and see what the development agencies, including the World Bank, did in agriculture. In 1975, about 20 percent of development assistance went to agriculture because it was, in my view, correctly perceived that agriculture was one of the bedrocks on which countries developed. By 2008, agriculture had slipped from 20 percent to around 3 percent of official development assistance.

Why? Like all things, it’s complex. One contributor was that there was a lot of opposition to modern agriculture from green groups, environmental groups and others who don’t like irrigation and large scale agriculture, just as there was opposition to large-scale infrastructure. There was also a sense that the private sector would take care of this. The private sector, of course, does do quite a bit with agricultural research, but there is an enormous role for the public sector as well.

So, we get to 2008 and I was actually in Brazil when the food crisis struck. The International Assessment of Agricultural Knowledge, Science and Technology for Development — a twenty million dollar project done by the World Bank and 17 other partners – then came out telling us why the Brazilian approach (heavily scientific, large scale, and technologically sophisticated) was the wrong way to go and that the right way was small, beautiful and organic. And the Minister of Agriculture of Brazil quite rightly tore me to pieces and said, “This is bizarre….”

(…) Fortunately, I think what is very good in the international scene is the rise of the middle income countries, like China, India and Brazil. They are much closer to the issues of poverty, much more pragmatic, much less ideological and bring much more common sense to the discussion.

Bizarre indeed. Thanks Marc — an important interview for everyone to read.

Could water undermine the American game plan for Iraq? Does a bear…

Tom Ricks links Will Rogers on the Iraqi water crisis:

Basra continues to perplex me. Weird news over the weekend out of there, as police fired at or over (not clear) demonstrators upset by the lack of electricity.

Meanwhile, my CNAS colleague Will Rogers checks in with other resources and utilities news. He reminds me of something I read years ago in a history of Iraq, that life there has always been a struggle against the people who live just upstream of your irrigation canal and can cut off your water-a tool the British used effectively in putting down the 1920 Shiite uprising.  

By Will Rogers
Best Defense deputy chief, Iraqi natural resources bureau

In Iraq, a country where one in four citizens do not have access to safe drinking water – let alone enough water to irrigate their crops — water shortages could drown any hope of long-term, meaningful reconciliation between the Iraqi people and the government.

Many Iraqis have been pleading to Baghdad to devote more resources to shore up the country’s crumbling infrastructure and unsustainable water management policies in order to effectively tackle the chronic water challenges that have been exacerbated by four-years of drought. “If our government was good and strong, we would get our [water] rights,” one Iraqi told The New York Times recently.

Ali Baban, Iraqi Minister of Planning and Development Co-operation, warned last July that Iraq’s intense drought conditions could push the frail state to a breaking point. “We have a real thirst in Iraq. Our agriculture is going to die, our cities are going to wilt, and no state can keep quiet in such a situation,” he cautioned. But with the government still in limbo after the recent March 7 election, it is unlikely that Baghdad will have the capability or capacity to address these water woes anytime soon.


Acute water shortages continue to shape internal security dynamics, forcing Iraqis to flee their native communities in search of better resources. Iraq’s Minster of Water, Dr. Abdul Latif Jamal Rashid, stated last year that more than 300,000 marshland residents were forced to flee their drought stricken communities in recent years. To make matters worse, in provinces where access to water is slightly better, the tattered infrastructure of pipes prevents much of that water from reaching Iraqis in their homes, forcing them to rely instead on water trucks from the International Committee of the Red Cross and other NGOs to supply fresh water.

Iraq was once a paradise, the wheat basket of the Middle East, with lush marshes and river ways that sustained a vibrant agricultural community and fresh-water fisheries. Even today, while agricultural production accounts for only 10 percent of Iraqi GDP, it has long been a hallmark of Iraq – producing wheat for world renowned German beers and the region’s most popular varietal rice, Anbar rice.

In recent years, many of Iraq’s crops have been left parched and its fragile agricultural industry in disarray – leaving Iraqi farmers in a veritable dustbowl. Barley and wheat production has declined up to 95 percent in provinces that rely on rain-fed irrigation, while total barley and wheat production declined by more than half last year. Meanwhile Iraq’s date industry – once the world’s leading exporter – is dwindling. At its height in the 1980s, Iraqi date farmers produced 600,000 tons of dates; in 2008, production dropped to 281,000 tons with production continuing to decline as drought worsens.

Regional politics and perennial drought throughout much of the Middle East have not helped Iraq navigate its water crisis either. Voluntary commitments from neighboring Iran, Turkey and Syria to increase water flow from upstream dams and reservoirs have been made over the last several years, but Iraq has not seen much increase in downstream water flow. The lack of credibility in the new government may also be hampering its ability to get its neighbors to execute on those commitments.

While much attention is understandably on Afghanistan, U.S. national security policymakers should be aware of the challenges that could shape the future security environment in Iraq – especially as the new government in Baghdad struggles to stand on its own. Water shortages alone won’t cause a resurgence of violence, but the issue could be the straw that breaks the back of a (weak) fledgling government. As the United States looks ahead for opportunities to ensure long-term stability in Iraq, access to water may well be critical to the new Iraqi government’s credibility and our ability to responsibly withdraw.

Could 2010 really be the year that Iraq begins to unravel? Maybe. Maybe not. But one thing is clear: the broad outlines of a post-occupation Iraq are beginning to take shape, and some of the acute challenges that have been marginalized in the post-war years could increasingly undermine Baghdad’s credibility and long-term stability. If left unaddressed, water shortages could very well leave Baghdad hanging out to dry — and us, too.

Will Rogers is a researcher with the Natural Security program at the Center for a New American Security, a non-partisan, non-profit national security think tank in Washington, DC. He is an author of, most recently, Sustaining Security: How Natural Resources Influence National Security and Broadening Horizons: Climate Change and the U.S. Armed Forces.

[From Could water undermine the American game plan for Iraq? Does a bear…]

Selling water to the global poor

“I determined to put together the equivalent of an Apollo project for water,” he said.

This is exciting. Even better, it will work. Kevin McGovern was also the founder of KX Industries who developed the filter technology for PUR and Brita. Excerpt from Marc Gunther’s post:

(…) Sure, it sounds a little grandiose, but all successful entrepreneurs start with a big idea. And a key element to his approach is learning as much as possible from not only so-called experts but from the people he is hoping to serve.

“We have to build trust in the communities where we want to operate,” he explained. “The name of our game is not technology. The name of our game is distribution through a trusted system.” TWI has put together a protocol that it uses to roll out its network–you can find a summary of the company’s eight step process here.

While the notion that clean water is a human right has obvious appeal, McGovern made The Water Initiative a for-profit business to create economic incentives for people to buy and maintain the units, replace the filters and take a sense of ownership over the problem. He hopes to create thousands of micro-entrepreneurs all over the world.

“We can make a lot of money and we can create a lot of change,” he says.

Water wars: All-American Canal

The loss of water in unlined canals is considered a disgrace (and opportunity) in Australia. So when I read about the lining of the All-American Canal I thought “good on yuh”. I still think that is correct, but for the Imperial Valley it is not as simple as I thought. For one thing, there are a lot of farmers who have benefited from the seepage into the water table.

“It was really tough. In the water world, nobody trusts anybody. Every time you try to work with anything in the water world, it’s five times harder,” said former Assembly Speaker Bob Hertzberg, a Los Angeles Democrat who helped negotiate the funding package.

The fight shifted to the courts, involving tiny Calexico and the mighty U.S. Congress. Calexico joined environmental and economic interests on both sides of the border in suing to block the lining. Pressured by powerful water interests and the Bush administration, Congress intervened to put an end to litigation by approving a last-minute rider to a tax bill ordering completion “without delay.”

More than two years later, there is still fear on the Mexico side, where much of the produce grown is exported to the United States.

“I felt like the water was mine,” said Geronimo Hernandez, whose 370-acre family farm is near the Algodones border crossing.

In the 1940s, Hernandez’s father, Miguel, had watched helplessly as his fields were flooded by seepage from the All-American Canal. As a remedy, the Mexican government built the La Mesa Drain, which to this day allows Hernandez and his neighbors to irrigate their crops. They are painfully aware that this supply will soon vanish.

“This will affect everybody,” said Alfonso Cortez Lara, a Mexicali-based researcher for a Tijuana think tank. He estimates the annual water loss could be equivalent to the yearly domestic consumption of Mexicali, with a population of nearly 1 million.

Oil and Water

The second guest post at Freakanomics by David Zetland– which concludes surprisingly that:

Bottom Line: We don’t have a gas shortage because gas is expensive; we will have a water shortage until water is expensive. Want more water? Pay for it.

Zetland’s post Anti-Capitalists get’s right down to the basic elements of public vs private – demonstrating how easy it is for a sincere “organizer” to misunderstand how we can organize private companies to efficiently deilver the public goods we all want.

Private vs Public Water Provision

One issue I’ve been puzzling over is whether there is clear empirical evidence on the superiority of either mode of organizing water utilities. I suspect that private vs. public matters much less than how well the provider’s incentives are designed – and of course whether prices reflect market clearing.

I recommend David Zetland’s convenient blog category “private vs public” to access his posts that touch on this topic. Included are a number of useful resource links. E.g., International Water Pricing: An Overview and Historic and Modern Case Studies.

Another useful example of empirical work is this one: Private vs Public Water Provision based upon some good work by UCSB masters students

Readers will know that I favor neither public nor private (investor-owned) provision of water, since the problems of ownership structure are less important than the problems of monopoly. (And the solution to monopoly — if not competition — is careful community monitoring.)

For more evidence on what does and does not matter, read this group project [PDF] by five UC Santa Barbara masters students.

Our research identified two primary differences between the public and privately owned water utilities in Thousand Oaks:

The privately owned water providers operate with greater efficiency than the public utility on three of the four indices of operational efficiency we evaluated;

The publicly-owned water provider charged significantly lower rates in the privately owned water providers for the 15 year period examined.

There was no significant difference between the providers on the basis of infrastructure investment and condition, water quality, water conservation, or customer satisfaction.

Read the whole report (232 pp) to get a serious dose of facts.

Bottom Line: There are tradeoffs between public and private ownership. If they’re weren’t, ALL water would be provided by one or the other!

The Water Shortage Myth

David Zetland is the S.V. Ciriacy-Wantrup Postdoctoral Fellow in Natural Resource Economics and Political Economy at U.C. Berkeley. Here’s an excerpt from a 2007 Forbes piece he did on Los Angeles water economics:

If water was priced to reflect scarcity, a decrease in supply would lead to an increase in price, and people would demand less. Consider another precious liquid: oil. Despite popular perception, there is no shortage of oil; supply does equal demand at the present price. It’s just that supply meets demand at a higher price than it did a few years ago.

In a sensible water pricing system, everyone would be guaranteed a base quantity of water at a low price. Those who used more would face a steep price hike.

As it stands, Los Angeles households pay $2.80 for the first 885 gallons they use per day. That’s enough water to fill 18 bathtubs. The next 18 tubs cost $3.40, which is only 20% more. Most L.A. households don’t even see this price increase, since the average household of three uses just 350 gallons–about seven bathtubs–each day. For that water, the household pays only $35 a month. If they use twice the amount, the bill merely doubles.

I propose a system where every person gets the first 75 gallons, or 1.5 bathtubs, per day for free but pays $5.60 for each 75 gallons after that. Under my system, the monthly bill for the average household of three would come to $95.

My system is designed to reduce demand rather than cover costs. Revenue paid by guzzlers would cover the costs of those who use only a small amount of water. Any leftover profits could be refunded to consumers or used to enhance the quality or quantity of the water supply.

We can solve America’s water “shortage” in the same way that we would solve a shortage in any market. Increase prices until the quantity demanded falls to equal supply. This pricing system would ensure that everyone gets a basic allocation of cheap water while forcing guzzlers to pay a high price.

Want to use more water? Pay for it.

Water shortages are created by an abundance of government rein

Figure 1: Total Volume of Water in “Melbourne Water” Storages

I like Chris Brown’s critical thinking (Chris is at the Australian Graduate School of Entrepreneurship at Swinburne University). How can you resist essays with the encapsulation of an idea as succinct as the caption of this post? The target Chris Brown post is on the topic of water economics — the context is Australian misadventures in governance, but the principles are the same everywhere.

It is near impossible to imagine any private company not enjoying the “problem” of high demand for its products and services. Yet there are some products that are repeatedly reported as shortages. There is one thing these products have in common: government intervention, typically in the form of price controls.

This is especially the case with water in Melbourne, Australia, and has been for at least a decade. While supply of water is in many ways a complex issue, understanding economic shortages is not.

The government has blamed the shortage of water on drought and climate change. And while droughts may be created by a shortage of water, water shortages are created by an abundance of government rein. Despite almost yearly decreases in water storages in Melbourne (see figure 1), real prices have not increased significantly. And currently the “Essential Services Commission” will be setting prices for the next five-year period. This means, regardless of supply or any number of variables and uncertainty, (real) prices will remain roughly the same for five years. In other words, expect continued shortages.

Instead of economical pricing there is political pricing, where pressure groups and special interests are given “rights” to use water during droughts, and at subsidized pricing. Businesses are able to use water for irrigation in the name of boosting GDP, while individuals are asked (or forced) to consume less and less. Government as the friend of the little guy is simply a myth.

Of course one may argue that water is a scarce resource, and, therefore, naturally there may be shortages. Yet all resources are scarce; water is no different from wheat or copper in this respect. Shortages do not exist in a free market because of the price system, including the profit-and-loss mechanism.

Most of the essentials of a water market are covered, so do read the whole thing. And thanks to U.C. Berkeley economist David Zetland for the link. I agree with David’s caveat on privatization:

I recommend the whole thing with one caveat: I do NOT think that water needs to be privatized to create the proper incentives for conservation, since private monopolies can be just as inefficient as public ones. What’s needed is better community control of water — so that it’s used to maximize total welfare.